I used to do this commute regularly, through Lowu. For an hour door to door, assuming you work close to Lowu, you will have to be on the East Rail line close to MTR. Forget Sai Kung, even with a car it's a royal pain as I know!
If you want a sea view then look at Tai Po, you can get some great places out there in your budget that will tick most of the boxes although it's not exactly an expat area, there are however quite a few expats around. Other areas, well Shatin as mentioned - quite a few expats and expat bars in Tai Wai although no sea view. The closest you can get is a river view. But your budget will get you into Shatin Heights area which is low density and favoured by those with a good housing budget. You could also consider Kowloon Tong, although unless you go to Festival Walk it lacks for eating out and since they closed the King's Arms there are no bars where expats hang out. However you are on the East Rail line there and also have buses to Shenzhen Bay if you want to cross over to Shekou area.